Transactions on Additive Manufacturing Meets Medicine
Vol. 5 No. S1 (2023): Trans. AMMM Supplement
https://doi.org/10.18416/AMMM.2023.2309817

Medical Aids and Devices, ID 817

TPMS structures delay clotting in extracorporeal blood contactors

Main Article Content

Lukas Hirschwald , Franziska Hagemann (DWI – Leibniz-Institute for Interactive Materials e.V., Aachen, Germany), Maik Biermann (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Patrick Hoffmann (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Tim Höhs (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Florian Neuhaus (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Märthe Tillmann (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Petar Peric (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany), Maximilian Wattenberg (Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering, Lübeck, Germany), Maik Stille (Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering, Lübeck, Germany), Tamara Fechter (University Hospital Aachen, Department of Anesthesiology, Aachen, Germany), Alexander Theißen (University Hospital Aachen, Department of Anesthesiology, Aachen, Germany), Patrick Winnersbach (University Hospital Aachen, Department of Anesthesiology, Aachen, Germany), Kai Barbian (Department of Cardiovascular Engineering, RWTH Aachen University, Aachen, Germany), Sebastian Jansen (Department of Cardiovascular Engineering, RWTH Aachen University, Aachen, Germany), Bettina Wiegmann (Department for Cardiothoracic, Transplantation and Vascular Surgery, Hannover, Germany), Matthias Wessling (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany; DWI – Leibniz-Institute for Interactive Materials e.V., Aachen, Germany), Christian Bleilevens (University Hospital Aachen, Department of Anesthesiology, Aachen, Germany), John Linkhorst (Chair of Chemical Process Engineering, RWTH Aachen University, Aachen, Germany)

Copyright (c) 2023 Lukas Hirschwald, Franziska Hagemann, Maik Biermann, Patrick Hoffmann, Tim Höhs, Florian Neuhaus, Märthe Tillmann, Petar Peric, Maximilian Wattenberg, Maik Stille, Tamara Fechter, Alexander Theißen, Patrick Winnersbach, Kai Barbian, Sebastian Jansen, Bettina Wiegmann, Matthias Wessling, Christian Bleilevens, John Linkhorst

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Abstract

Membrane oxygenators or dialyzers are state of the art blood contacting devices based on hollow fiber membranes. Due to the straight shape of the hollow fibers, boundary layers are formed, which must be intermixed to increase mass transfer. Recent research focuses on using triply periodic minimal surface (TPMS) structures for the blood phase in extracorporeal circulatory devices. These structures can only be additively manufactured as their geometry is intertwined with undercuts. TPMS structures have continuous, periodic, and tortuous flow channels that introduce radial mixing in the laminar flow regime [1,2]. This study incorporates TPMS structures into housings utilizing the inlet and outlet regions for fluid distribution and collection for the first time. Three modules are compared: a hollow fiber imitating tubular module (tubular), an isotropic TPMS module (isoTPMS) with unit cells of the same size, and an anisotropic TPMS module (anisoTPMS) that has distorted unit cells, imitating the cardiovascular system and reducing shear rate peaks and leaps. In these modules, the coagulation behavior of human blood was examined by serial experiments, looking at various coagulation parameters and visually inspecting formed clots via computed tomography (CT). These human blood experiments are backed up with experimental residence time distribution (RTD) measurements and simulative data of hydrodynamic investigations. With these simulations and experiments, we were able to show that TPMS structures delay the coagulation of blood, resulting in less obstructive blood clot formation compared to the tubular structure.


Author’s statement
All authors state no conflict of interest. Informed consent has been obtained from all individuals included in this study. The blood was withdrawn from healthy volunteers after approval from the ethical committee of the University Hospital of the RWTH Aachen University (file no EK22-355) and informed consent. Wessling acknowledges DFG funding through the Gottfried Wilhelm Leibniz Award 2019 (WE 4678/12-1). This project has received funding through the DFG Priority Program SPP2014 “Towards an Implantable Lung” and European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 694946).


References
[1] F. Hesselmann et al., “Structure-dependent gas transfer performance of 3D-membranes for artificial membrane lungs,” J. Memb. Sci., vol. 634, no. May, p. 119371, Sep. 2021.
[2] F. Hesselmann et al., “TPMS-based membrane lung with locally-modified permeabilities for optimal flow distribution,” Sci. Rep., vol. 12, no. 1, p. 7160, May 2022.

Article Details

How to Cite

Hirschwald, L., Hagemann, F., Biermann, M., Hoffmann, P., Höhs, T., Neuhaus, F., … Linkhorst, J. (2023). TPMS structures delay clotting in extracorporeal blood contactors. Transactions on Additive Manufacturing Meets Medicine, 5(S1), 817. https://doi.org/10.18416/AMMM.2023.2309817

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